Electric cooking system



May 24, 1938. E. O. SCHWE|TZER ELECTRIC COOKING SYSTEM Filed March 15, 1955 2 Sheets-Sheet 1 May 24, 1938. E. o. SCHWEITZER 2,118,116

ELECTRIC COOKING SYSTEM Filed March 15, 19:55 2' Sheets-Sheet 2 8 j m mm zifi c e 67:

Patented May 24, .1938

PATENT orries 2,118,3116 morale cocaine srsrw Edmund o. Schweitzer, Northbrook, Application March 15, 1935, Serial No. nails 12mins.

This invention relates to electric cooking systerns, and more particularly is directed to electrically operated ranges for domestic and industrial uses.

Electrical ranges of the type now in use rely,

in the main, on the provision of surface heating units, formed in the shape of flat spirals or the like, and either enclosed within metallic tubing, or set into grooves in a porcelain or similar refractory brick. Such ranges are operated almost entirely by conduction of the heat generated by the resistance unit through the lower surface or bottom of the pots, pans or other culinary utensils in which food is to be cooked. This heat conduction is in an upward direction through the bottom of the utensil and also radially outwardly toward the lateral surface of the utensil. As a result, heating of the materialto be cooked is effected by conduction of externally applied heat into the utensil through the lateral and bottom walls thereof and toward the center of the utensii. This results in a loss of efllciency, due to the fact that before heat is actually applied to the material to be cooked, it is necessary to heat up the relatively large external surface of the unit. These 'uten'sils, as recently developed, have been provided with polished external surfaces still further reducing the transmission of heat into the interior of the utensil. Also, if the utensils are of the double-walled type having an annular ring of insulating material or the like therein, it is apparent that the insulating barrier must first be heated up before transmission of heat therethrough into the interior of the utensil can be obtained.

The present invention is directed to a cooking system wherein the heat is applied substantially centrally within the utensil, and by conduction and radiation is transmitted through the material to be cooked toward the outer surfaces of the utensil. Thus the heat is immediately applied to the material to be cooked and no heat loss from the utensil is entailed until after the heat has passed entirely through the material within the utensil.

In a preferred embodiment of the invention, I provide a cooking system wherein the utensils are formed with a hollow internal core or dome, 1 which is centered above a vertically adjustable electric heating member of. the space heating type, that is, a helical or cylindrical electrical resistance unit carried upon an axially extending heat refractory core, the core being adjustable vertically within the hollow recess of the utensil. Thus the heat generating means is posi- (or. are-4'1) tioned substantially centrally within the utensil, with themateriol to be cooked surrounding it, and the transmission 0! heatis hence directly through the internal dome into thefood or other material to be heated or cooked.

By the use of a double-walled insulated pot or utensil, the emciency of such a cooking system can be measurably increased, due to the fact that the insulation is in the proper position forpreventing escape oi heat from the utensil, and 10 hence confines the heat therein. However, even without such insulated construction, the rate of cooking is substantially increased. over that poduced by the surface units heretofore employed beneath the bottom of the utensil, since the apl5 plication oi the heat allows its immediate use for cooking instead of preheating p rposes.

One object of the present invention is the provision oi a cooking system wherein heating of the ioodstuffs within a cooking utensil is effected by 39 transmission of heat from the center of the utensil outwardly toward the lateral walls thereof through the material to be cooked.

Another object of the present invention is the provision of a heating unit for cooking material within a pot or the like, which unit is adiustable as to its position with respect to the center of the pot.

A still further object of the invention is the co-, ordination of cooking utensil construction with 30 an electric heating unit of the helical cone type, in such manner as to effect most efiicient transmission of heat to the material which is to be cooked within the utensil.

Another feature of the present invention is the 5 modification oi electric cooking systems so as to eflcct direct transmission of heat to the material to be cooked by both radiation and conduction.

An important advantage secured by my inven- 40 tion is the provision of a structure which'results in appreciable reduction in the time elapsing between energization of the heating means and application of the heat produced thereby to the material to be cooked. 45

Another advantage secured by the present invention is the fact that no heatv loss through the side walls oi the cooking utensil occurs until after the heat has been transmitted entirely through the irnaterial being cooked within the pot or pan. 0

Other objects and advantages of the present invention will appear more fully from the following detailed descripticn, which, taken in conjunction with the accompanying drawings, will disclose to those skilled in the art the particular 55 modified forms of cooking utensils to be used with the present type of cooking system;

Figure 7 is a diagrammatic circuit showing one manner of effecting electrical connection to the heating units of the present invention; and

Figure 8 is a diagrammatic circuit illustrating another manner of effecting electrical connection to the heating unit of the present invention.

Referring now in detail to the drawings, I have shown in Figure l a range 5, supported on a floor or other surface by suitable legs 8, having a storage compartment 1!, oven compartment 8, and a broiler compartment 9.

The range of Figure 1 is of the console type, having a flat top surface, extending across the entire width thereof, and provided with a back panel W. A suitable electric clock or similar timing member may be mounted in the back panel, as shown at l2.

A control panel for the range is shown at N, having control members M for controlling each of the top heating units or range heating members, and a control member is for controlling the heating unit within the oven 8. The top slab covering the oven part of the range is indicated generally at I8, and, as shown in Figure 2, preferably comprises a porcelain or similar refractory slab member, having openings through which a plurality of individual heating units H are adapted to project. Preferably, four of such units are employed in the range shown in Figure 1.

Considering now Figures 2 and 3 in more detail, the slab I6 is provided at spaced points with openings adapted to receive suitable cylindrical sleeve members l8, which sleeve members are provided with a plurality of perforations I9 providing for flow of air into the interior thereof. The sleeve l8 extends downwardly for a-considerable distance below the lower surface of the slab l6, and provides, in effect, a flue or chimney for the heating unit II.

This heating unit comprises an electrical resistance wire 20, wound in a suitable spiral groove formed in a suitable heat insulating cone 22, which may be formed of porcelain or other similar refractory material. A suitable cap member, formed of the same material, is indicated at 28. The lower portion of the cone 22 of the unit l1 terminates in a supporting portion 24, carried within an annular flanged portion 25 formed at the upper end of the socket member 26, which socket member is carried within an opening formed in a flanged collar member 21, the flange portion 26 of the socket 28 having bearing engagement about the defining periphery of the opening in the collar 21 within which the socket 28 is suspended. The core 22 may be suitably secured within the flange 26 by bent over tab fingers or the like, as shown.

The collar 21 is mounted in a suitable carrier member 28, comprising a plurality of cylindrical bands 29 joined together by means of spaced vertically extending strips 80, the carrier 28 besnails ing open between the strips and bands 25) to provide for free flow of air through the porterstion ifi'into the interior of the carrier. At one defining vertical surface of the carrier 28 there is provided a suitably perforated member 32. forming attack, the member 32 having a plurality of laterally extending slots therein adapted to be .igaged by the projecting teeth 33 of a pinion member 34. The member 34 is suitably keyed or otherwise secured for rotation on a shaft 35 extending forwardly through the control panel it of the range, and provided with an operating handle l4.

The shaft 35 is suitably supported for rotation by a pair of bracket members 36 secured to the sleeve H8 in any suitable manner, as by welding, soldering or by screws or rivets. The brackets 38 are joined, at their extending ends, by cross members 81 forming a suitable enclosure for the pinion 34. A leaf spring member 38 is mounted upon the external surface of one of the cross members 31 by means of a screw 39, and is provided with a suitable engaging portion 40 adapted to have resilient engagement between adjacent teeth 83 of the pinion 34 for holding the pinion 34 in any desired adjusted position.

Mounted within the extending portion of the bracket 88 upon the shaft 35 is an insulating col-' lar member 42, which member is provided about the major portion of its periphery with a metal contact ring 43, the ends of the arcuate ring 43 being spaced apart by an insulating block member 44 set into the collar 42. The collar 42 is adapted to have rotary movement upon rotation of the shaft 35, and thereby effects rotation of the contact ring 43 upon rotation of the pinion 84, and consequently in accordance with raising or lowering of the carrier member 28 carrying the heating unit H.

A pair of contact members 46 and 41, respectively, are adapted to have contact bearing engagement about the external surface of the ring 44, and when the device is in position such that the heating unit I! is in its lowermost position, the insulating block 44 will be in engagement with one of the contacts, such as contact 46, while the other contact 41 will be in engagement with the metallic ring 43. Upon rotation of handle or control member l4, the shaft will effect rotation of pinion 34, thereby raising the carrier 28 and heating unit l'l above the surface of slab l6. At the same time, by the rotation of member 42-the block 44 will be rotated out of engagement with the contact 48, and consequently contact will be effected between the contacts 46 and 41 through ring 43.

This completes a. circuit between conductors 48 and 48, and thereby completes a circuit to the heating unit through conductors 48, 49, and 60, the conductors 48 and 49 forming portions of one conductor leading to the terminal 52 of the socket member 26, while the conductor 50 leads to a terminal 63 of the socket member 46. These conductors are led to the heating unit from a source of current supply through an insulating cable, such as cable 54, and the particular circuit connections will be described in detail later.

The contacts 46 and 41 are supported in position for engagement with the contact ring by means of an insulating block member 55, secured between the extending portion of the bracket 36 in any suitable manner, as by the bolt 56. The members 46 and 41 are resilient spring members, having wiping engagement along the contact surface, and being normally urged into pressure contact therewith.

It is apparent, therefore, that upon initial rotation of shaft 35 to raise the unit H from its lowered position, in which position the cap member' 2! lies flush with the upper surface of the slab member i6, contact will be effected between the contacts 46 and 41, closing the circuit to the heating unit I1, and consequently causing energization of the heating coil 20 for heating purposes.

As shown somewhat diagrammatically in Figure 1, the heating units I! are adapted to extend into suitable domes or recesses formed inpot members 82, or other types of cooking utensils, The members 62 are adapted to contain material to be cooked, such as indicated at 83 and N, the

material 84 being carried upon an auxiliary supporting tray 8! seating within the interior of the pot 62 on the upper surface of the dome or recess 60. when the units are raised to their upward limiting position, theyare fully enclosed within the recesses. 80, and consequently the heat generated thereby will be transmitted laterally outwardly and upwardly from the unit, thus effecting complete and rapid heating of-the food materials 83 and 84.

Referringnow in more detail to the construction of the various cooking utensils which may be employed in the present electric cooking system, in Figures 4, 5, and 6 I have disclosed several forms of such utensils. However, it is to be understood that the invention is not limited to these specific forms of utensil, but may be employed for any of the desired types of cooking utensils which are now commonly employed for culinary purposes.

In Figure 4 I have illustrated a roaster, which may also be employed as a boiler or basting oven. The roaster is indicated generally at 86, and comprises a double walled utensil having the walls B'i and G8, which are suitably spun and joined, as at 69, the space between the walls 63 and 88 being filled with suitable insulating material 10. This insulating material may comprise mineral wool, or any other type of fibrous or mineral heat insulating material. The bottom wall of the utensil is formed as a sheet member, indicated at I2, and provided with integral spaced recessed portions 13 and H. The recesses '13 and 14, in a roaster of this type, which is usually elliptical in shape, are preferably centered with respect to the respective focii of the ellipse, so that distribution of heat will be substantially uniform throughout the master.

The roaster is provided with an upwardly con caved cover member 15, which has seating engagement in the shallow ring formed by the joining of the walls 61 and 68 at the Junction 39. The domes I3 and I may be of frusto-conical shape, andare joined to the bottom wall 12 of the roaster by smoothly curved fillets or joining surfaces, thereby providing no sharp corners in which food particles or the like may be deposited, and facilitating cleaning of the utensil. The upper ends of the recesses 13 and M are closed, either by integral portions of the defining walls of the recesses, or by separate closure plates Joined thereto by smoothly curved portions. If desired, the upper surfaces of the domes l3 and I4 may be employed as supporting surfaces for supporting a shallow tray 16 within the roaster, which tray may contain meat or similar food to be cooked, indicated at .11, the tray being provided with spaced fluted edge portions 1! providing for passage of steam from the water I! within the bottom of the tray upwardly past the tray and over the surface of the material to be cooked, the eby basting the same.

It will be apparent that the heat generated by the unit I! will be conducted through the walls of the recesses 13 and 14 into the water I! surrounding the same, and will thereby be transmitted radially outwardly toward the side walls of the container. However, the water will be thoroughly heated before any heat is lost through the side walls l1 and 68 of the roaster, and consequently the heat will be applied to the bottom of the tray 16 before any appreciable heat loss is sustained through the lateral side walls of the roaster. This provides for the efficient transmission of a heat to the material to be cooked, since no heat loss is occasioned prior to the application of heat directly to the material to be cooked. v

In Figure 5 I have provided a modified form of pot or pan, which may be a pan of the ordinary sauce pan type, or any desired type of pan, preferably shown with double walls Eli andiiil he tween which suitable insulation 83 is disposed. The lower or bottom surface 8 3 of the pan is pro vided with an integrally formed downwardly opening dome 85, within which is adapted to be projected the heating unit ii, the bottom 85; of

the pan being adapted to rest upon the upper surface of the slab member 93. The inner wall 80 of the pan isprovided with upwardly extend ing spaced ribs 86, which ribs provide a suitable support for a shallow pan 81 upon which may be supported anysuitable material to be fried, roasted or otherwise cooked. If this pan ST is not to be employed, the same may be removed, and the pot can then be employed for cooking vegetables; such as potatoes, or simiiar vegetables cooked in water, or for cooking or canning fruit or the like. In Figure 6 I have shown a modified type of pan indicated at 90, which is provided with the b0ttom wall 92, in which is set a suitably inverted cup-shaped glass dome 93, formed of heat resistant glass, such as Pyrex or the like, and which is adapted to form a recess to receive the heating unit i'l. By the use of such a glass dome, both radiant and conducted heat are transmitted to the material within the pan 9!), and consequently the material may be cook-ed by radiant heat, thereby securing all the benefits of such heating. The' peripheral edge or dome 83 may be suitably cemented or otherwise secured in an annular groove or the like formed in the bottom wall 92 of the pct 95. f

It is to be understood that each of the pots disclosed may be of thesingle wall type, if desired, without in any way departing from the scopeof the present invention. While I have found that double walled utensils are desirable, inasmuch as they prevent lateral heat loss from the interior of the utensil, andthereby confine heat within the utensil, it is understood that single walled utensils of the typenow commonly in use may also be employed. I

It will be noted that by theprovislon of pots or :utensils having the upwardly'extending internal domes or recesses into which the heating unit I! may be projected, the heat from the unit il will not be carried away by drafts, air' curre'nts or the like, .but will be directly communicated through utensil.

However, if the side walls are insulated, this heat will not be readily dissipated through the sulation, and consequently the'efllciency oi the application of heat can be measurably increased by providing insulating walls for the utensils. However, it is apparent that such walls need not be provided in order to carry out the underlying principles of the present invention, and that even without such walls the efiiciency of the electrical application of heat by means of supplying this heat substantially centrally oi the utensil is HIEESI- urably increased over the surface type heating unit now in common use.

While I have disclosed only a very few of the large number of dlfierent types of cooking lltl'l sils which are employed for culinary purposes, it is to be understood that any desired type or shape of utensil now employ may be provided with a suitable recess in the bottom thereof for receiving the heating means. The invention is therefore applicable to double-broilers, coffee pots, Dutch ovens, and pots and pans of all descriptions.-

In Figure I I have disclosed one form of elec trical circuit for the range of Figure 1, when it is desired to connect the heating unit in parallel. A suitable source of current supply is indicated at 00, and is transmitted, through transformer I02, to the conductors Hi3 and I04 which extend into the range. The heating units I05, I06, I01, and I08, which comprise the upper or range heaters for the range 5, and which are controlled by the control members H, are connected across the conductors I03 and I04 in parallel. Each of the units I05, I00, I01) and I08 is provided with a suitable switching means connected to its control member I4, such as the collar 42 described in detail in connection with Figures 2 and 3, for effecting connection between conductors l8 and 09 to complete a circuit through these conductors and the heating units and the return conductors 50.

If it is desired to connect the units in series, such a connection is shown in .Figure 8, in which the'secondary side of the transformer I02 is provided with conductors H and H2, the conductor IIO being a return conductor connected to the endone of the heating units through the switch I I3. In this circuit, when it is desired to energize 1 the heating unit I05, for example, the switch IIQ is operated, shifting the circuit from the con- .ductor II2 to the contact II5, thereby completing a circuit through the resistance unit I05. In a respective control members IQ for each of the units I05, I08, I01, and I08, the control units themselves being also provided with switches, such as the collars 42, for effecting the complete connection to the resistance unit, or the switches H4, H6, H1, and H3 may comprise suitable switching means mounted on the control member as shown in Figure 2, but provided with a third contact whereby contact is switched from one of the conductors, such as conductor I I2, to the conductor I I leading to the resistance unit for completing the circuit through the unit.

' It is believed apparent that I have disclosed a method of heating which comprises positioning anionic nutted thereto passes to the side walls or the the heat generating means at the center of a cooldng utensil, and causing the heat generated thereby to be transmitted by conduction and radiation laterally outwardly through the utensil, and consequently through the material to be cooked, to the lateral side walls of the utensil. in addition, i have provided means for adjusting the position of the heating unit, which adjustment will vary the amount of heat transmitted thereby to the utensil, and I have also provided for automatically controlling the energization of the unit in accordance with its position.

do not intend to be limited to the exact details at construction which I have shown and described in connection with a preferred embodi ment oi the invention, but only insofar as limited by the scope and spirit of the appended claims.

I claim:

i. In a domestic electric range having a horizontal range surface, a plurality of helically wound vertically extending heat generating units,

energizing means therefor including a pair of spaced contacts, and means at the front of said range for adjusting said units vertically with respect to the range surface including a rotatable said range for moving said carriers to adjust said units vertically above said slab.

3. In combination, an electric range including --an electric heating element movable vertically with respect to the utensi1receiving surface of said range, a cooking utensil for use with said range having a bottom wall and a lateral defining side wall. and an inverted transparent heat resisting dome in said bottom wall disposed substantially centrally oisaid utensil and opening outwardly of the bottom of said utensil, said dome being adapted to receive said heating element.

4. In combination, a utensil having a bottom wall, a dome rising from said bottom wall and into the Interior of the utensil, said dome being' disposed substantially centrally within the uten- $11 at a position of maximum diameter of the utensil and formed of a material through which both radiant and conducted heat are adapted to be transmitted to the contents of the vessel, and a heating element extending from beneath the bottom of the utensil and up into said dome to substantially the upper end thereof for delivering radiant and conducted heat through said dome to the contents of the utensil.

5. In combination, a utensil of generally elliptical form and having a bottom wall, a pair of dome members integral with the bottom wall and rising up into the interior of the utensil and disposed at the focal centers of the utensil and at substantially the maximum diameter of the utensil, and heating elements extending from beneath the bottom of the utensil and up into said domes to substantially the upper ends thereof.

6. In combination, a range having a refractory plate, a utensil having a bottom portion adapted to rest upon said plate, a dome rising from the bottom portion of said utensil and into the interlor of the utensil and opening downwardly to receive a heating unit, a heating unit rising from beneath the bottom of the utensil and into said dome and comprising'an upwardly elongated heat insulating member having a resistance coil wound helically thereon, means for adjusting the extension of said heating unit above the top of said refractory plate a substantial amount, and a circuit for said heating unit closed when said unit is in fully raised position and through a substantial range of adjustment of said unit.

7. In combination, a range, an electric heating unit rising up above the top of said range and comprising an upwardly elongated heat insulating member having a resistance coil wound helically thereon, means for adjusting the extension of said heating unit above the top of said range a substantial amount, and an electric circuit for said heating unit closed when said heating unit is in fully raised position and through a substantial range of adjustment of said unit.

8. In combination, a range having a refractory plate, a sleeve member opening through said plate and depending therefrom, a carrier guided in said sleeve member, an electric heating unit supported by said carrier and rising above the top of said plate, a rack on said carrier, a pinion meshing with said rack for adjusting said carrier and heating unit vertically, a contact operable with said pinion and having an insulating portion, and contacts bearing against and connected by said first contact in certain positions of said heating unit, one of said last contacts bearing against the insulating portion of said first contact to open the circuit for the heating unit in another position of said unit.

9. In a domestic electric range having a horizontal range surface, a helically wound vertically extending heat generating unit, energizing means therefor including a pair of spaced contacts, and means at the front of said range for adjusting said unit vertically with respect to the range surface including a rotatable contact bridging member movable into bridging engagement between said contacts in predetermined adjusted positions of said unit.

10. A cooking utensil of the class described having a metal bottom wall provided with an opening therein, a lateral defining metal side wall, and an inverted transparent heat resisting dome secured to said bottom wall and closing the opening therein, said inverted transparent heat resisting dome extending upwardly over said opening into the interior of the utensil within said lateral defining side wall and opening outwardly of the bottom of the utensil.

11. A cooking utensil of the class described having a metal bottom wall provided with an opening therein, a lateral defining metal side wall, and a transparent heat resisting member secured to said bottom wall and closing the opening therein, said transparent heat resisting member being adapted to transmit both radiant and conducted heat to the contents of the utensil when the utensil is disposed with said transparent heat resisting member adjacent a heater externally of the utensil, at least a portion of the transparent heat resisting member extending upwardly over the opening in the said bottom wall.

12. A metal cooking utensil having in the bottom wall thereof a dome formed of material capable of transmitting radiant energy into the contents of the utensil.

EDMUND 0. SCHWE'ITZER. 

